The Blood Sugar - Cortisol Connection
What Versus When
I could talk for DAYS about what to eat to improve your energy, reduce stress and balance your hormones (I frequently do!).
Fundamentally, we need to eat the right quantity of food (in terms of units of energy or “calories”) to derive enough energy to fuel vital physiological processes in our bodies. We also need the right ratio of macronutrients (carbohydrates, proteins and fats) and the right concentrations of micronutrients (vitamins, minerals and phytochemicals) to function well. So, it’s true that what we eat is incredibly important – especially in a modern world of mineral-diminished soils and an over-reliance on processed foods that are often deplete of the essential nutrients needed to sustain health.
But how important is when we eat and what’s the impact of meal timing and spacing on our energy, stress and hormones?
The Blood Sugar - Cortisol Connection
The principles of when we eat have been studied a lot in recent years, with the rise of intermittent fasting (IF), time restricted feeding (TRF), alternate day fasting and the likes of the 5:2 and other diets. Whilst evidence supporting certain health benefits of fasted feeding patterns has certainly grown, there is currently not enough evidence to determine whether these eating patterns are safe for younger female populations of a healthy weight. Indeed, most relevant human studies (to date) have been conducted on overweight, middle-aged male and post-menopausal adults.
One of the main problems of time-restricted feeding patterns (or simply going longer periods without food) is the effect it can have on cortisol (our main stress hormone). When our blood sugar drops, certain hormones including cortisol come to the rescue.
When blood sugar drops – cortisol rises
Cortisol is an adrenal steroid hormone and its main job is to keep us alive. Cortisol helps to wake us up in the morning, keeps us alert during the day and also helps us manage any dangers we may encounter. One of the ways it does this is by stimulating the release of glucose from different storage sites into the blood so that your muscles and cells have the energy to run or fight when under threat. When blood sugar is on the low side, this is one of the reasons that cortisol, alongside glucagon, epinephrine and other hormones, work so well.
The trouble is that our modern lifestyles are replete with stressors including emotional ones (pandemics, financial worries, relationship challenges, body image and mental health issues) and physical ones (illness, injury, intense exercise). When it comes to dealing with those stressors we only have one stress response! We recruit the same hormones, including cortisol, time and again to help keep the body safe.
In this regard, fasting, skipping meals, leaving too long between meals and yo-yo dieting – especially when we’re not overweight and we are already stressed out, could be a problem. In fact, the hormonal changes we see in response to low blood sugar can last up to 8 hours during which time blood sugar may be difficult to control and this creates a knock-on effect. We can end up feeling tired, wired, irritable, anxious, tense, craving sugar-laden treats and find it hard to sleep at night. Chronic increases in cortisol are also something we want to avoid. For more info on this topic, check out my blog on reducing stress.
How to Improve Blood Sugar Balance
So how can we balance our blood sugar to minimise these effects and is fasting to be avoided full-stop?
First things first, a daily 12 hour overnight fast is safe and recommended for most people. If you habitually and significantly extend this then it’s worth seeking advice from a qualified health professional to determine whether this is healthy for you.
Whilst every client is unique, in my clinic I find that leaving more than 5 hours between meals can start to cause issues with anxiety, irritability and other symptoms related to high cortisol. However, by making subtle shifts to meal composition and becoming a little more conscious of meal-spacing we can learn to optimise our blood sugar balance and make for a much smoother and more energised ride.
Energy and Hormone Balancing Blueprint
Maintain a 12-hour overnight fast – for example, if you finish eating at 8pm, don’t eat until 8am the next morning
Eat every 4-5 hours – we don’t want our blood sugar to start dragging it’s heels and this is the window that works best in my clinic and is also supported in research
Try not to eat in between this window – we want to allow our insulin levels (fat storing hormone) to find a natural baseline. HOWEVER, if you have missing or irregular cycles that have been diagnosed as hypothalamic amenorrhoea (HA), as opposed to polycystic ovarian syndrome (PCOS), I’d recommend leaving smaller gaps of 2-3 hours maximum.
At each meal, eat:
A source of quality protein - organic grass fed meat, wild caught fish, organic goats or sheep milk dairy, quinoa, pulses, beans.
Low GL, fibre rich foods - beans, pulses, whole vegetables and wholegrains.
Some healthy fats - oily fish, avocados, nuts, seeds, olive oil, organic grass-fed butter and coconut oil.
Save high GL/sugary foods for a treat – these foods have a negative effect on blood sugar balance. If you have HA you can include these foods too when you want them, but do balance your meals as I’ve suggested in point four.
If you find this helpful, do share it and get in touch if you need more support.
Holly x
© Holly Dunn Nutrition